1. Field of the Invention
The present invention relates to apparatus for remote sensing of drilling mud oil content to detect the presence of native hydrocarbons encountered downhole while also distinguishing from any oils that may be present in oil-base drilling muds.
2. Prior Art
There are presently a number of differing methods that rely upon fluorescence induced by ultraviolet light for indicating the presence of hydrocarbons. U.S. Pat. No. 2,591,737 is representative of an early form of drilling mud monitoring device that tests for crude oil presence by detecting characteristic fluorescence. This method employs steam distillation prior to treatment that enables visual inspection and identification of any oils present in the sample. U.S. Patents No. 4,692,611; 4,672,218; and 4,662,749 are illustrative of the use of fiber optic cable in remote sensing applications. Finally, U.S. Pat. No. 4,609,821 provides a method for testing for the presence of native hydrocarbons from a wellbore by testing a drilling mud sample for ultraviolet fluorescence response. This patent teaches the extraction and preparation of a test sample from a drill cutting present in the drilling mud flow. The prepared sample is then irradiated with ultraviolet light and synchronous excitation/emission relative intensity data is generated to give an indication.